High-potential-energy detector.



UNITED STATES Patented September 6, 1904.

ATENT Fries.

JOHN D. HILLIARD, JR., OF CLENS FALLS, NEV YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEiV YORK.

HIGH-POTENTIAL-ENERGY DETECTOR.

SPECIFICATION forming part of Letters Patent No. 769,652, dated September 6, 1904.

Application filed March 13, 1903. Serial No. 147,561. No model.)

To ftZZ 'Ich/0771, it 'llt/ty concern:

Be it known that I, JOHN D. HILLIARI),J1'., a citizen of the United States, residing' at Glens Falls, county of Tai-ren, State of New York, have invented certain new and useful improvements in High-Potential-Energy Detectors, of which the following' is a specification.

The high-potential-cnergy detectors heretofore in use have been of complex or fragile construction and in the nature of' laboratory apparatus, and according'ly not adapted for general use by the non-scientific.

The object of my invention is to provide a handy and inexpensive device by means of which the ordinary workman may safely and quickly detect the presence of a dangerous voltage in a conductor.

The device consists of induction-plates suitably supported for safe handling' and so arranged that by their condenser action a discharge takes place in the form of a torrent of sparks when one of the plates is brought into proximity to a highly-charged conductor.

My invention will be more readily understood by reference to the accompanying drawings, forming a part of the specification, in which4 Figure l is an axial section of one end of a switch-stick with a high-potential-energy detector embodying one form of my invention thereon. Fig. 2 is a transverse section thereof in the plane of the spark-gap, and Fig. 3 is an axial section of a modified form of detector also embodying my invention.

ln the construction shown in Figs. l and 2, A represents a wooden switch-stick with the handle part broken ofi' and provided at its end with an ordinary switchhook l, having' a central tang 2, extending' into the end of the stick, and a ring-flange 3, surrounding the end thereof. The hook l is secured in place by a transverse screw passing' through a side of' the flange 3, the central tang 2, and the end portion of the stick and engaging a tapped hole in the opposite side of the flange. An induction-plate 4 is bent into the form of a shell or cylinder about the stick A, with its upper edge some distance below the hookiiange 3, and in order to provide greater space for the insulation l prefer to set the plate 4 into a shallow groove turned in the side of the stick A, so that the outer face of the plate shall be in line with the surface of the stick. Surrounding the plate 4C and the stick A is a layer of insulation 5 of' the same thickness as the ring-flange 3 and extending from the lower edge thereof to a considerable distance below thc lower edge of the plate #l to provide ample creeping-surface. A second plate, 6, in the form of a shell or cylinder, fits over the ring'- flang'e 3 and the insulation 5 and extends from the upper edge of the flange to near the lower edge of the insulation. The joint between the plate 6 and the fiange 3 of the hook may be made by a driving fit or by brazing.

A spark-gap by which the induced charge may jump from one plate to the other is provided near the lower edges of the plates 4e and 6. A notch 7 is cut in the lower edge of the outer plate (5, and a depending finger 8 is secured to the cylinder above the notch and with its lower end overhanging the notch. rlhe wall of insulation and the inner plate 4t are pierced in line of the center of the notch 7 for the passage of an adjustable spark-point 9, consisting of a screw carried by a threaded disk l0, secured to the inner surface of the inner plate 4. A transverse hole ll is provided in the stick A, the opposite walls of the plate 6, and the insulation 5 for the introduction of a screw-driver when it is desired to adjust the position of the spark-point 9 with relation to the finger S.

lVhen the switch-hook l or any part of the metallic cylinder (5 is brought into proximity to a charged electric conductor, a static charg'e is at once induced in the inner plate 4, which instantly discharges between the linger S and point 9 in the form of a readily-perceptible succession of sparks, and at the same time the workman is protected from shocks by the insulating property of the wooden stick.

The modification shown in Fig. 3 consists of a vessel B, of glass or other transparent insulating' material,provided with a metallic lining' in two sections 20 and 21, separated at C to forma small spark-gap. To the upper section 20 of the metallic lining a metallic hook 22 is connected in any suitable manner. This device is adapted to be hung by its hook 22 upon an electric conductor and operates in the same manner as the device first described in the presence of high-potential energy, the discharge being readily observable through the transparent walls of the vessel B. The Vessel B serves also as a means for effectually protecting the operator from shocks when the device is being handled.

It is apparent that my invention is capable of embodiment in many forms and is in no way restricted to constructions shown in the drawings.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. A voltage-detectorl comprising a metallic contact connected to a metal plate, a secondA plate insulated from the rst plate and in inductive relation therewith, and a readily-observable spark-gap between said plates.

2. A voltage-detector comprising an insulating-handle, and insulated conducting-surfaces supported by said'v handle and provided with a spark-gap.

3. A voltage-detector comprising an insulating-handle, and insulated conducting-sur- Afaces supported by said handle and provided with an adjustable spark-gap.

4:. A voltage-detector comprising an insulating-support whereby it may be safely handled, metal plates carried by said support in inductive relation to each other and provided with a readily-observable spark-gap, and a metallic contact carried by one of said plates.

5. A voltage-detector comprising an insulating-support, and inner and outer metallic shells or plates separated by insulation and surrounding said support, the outer shell having a projecting finger thereon and the inner shell having a discharge-point carried thereby projecting outwardly into proXimity to said linger.

6. A voltage-detector comprising an insulating-support whereby it may be safely handled, and inner and outer metal plates or shells separated by insulation and surrounding an end of said support, the outer shell having a notch in one edge and a finger connected thereto and overhanging said notch and a dischargepoint carried by the inner Vshell in line of said notch and projecting through the insulation between the plates into proximity to said finger.

7. A voltage-detector comprising an insulating supporting-stick provided' at one end with a metallic contact, inner and outer metal plates surrounding the end of said stick and separated by a layer of insulation, the outer pla-te being connected at one edge to said contact and having in its opposite edge a notch, a inger connected to said outer plate and overhanging said notch, and an adjustable contactpoint carried by said inner plate and projecting through the layer of insulation into proX- imity to said linger.

In witness whereof I have hereunto set my hand this 7th day of March, 1903.

JOHN D. HILLIARD, JR. Witnesses:

CHAs. H. CARSON, GLENooRA BEAUDOIN. 

